priming carb all the time
 

my 1994 mariah with 4.2 v6 has a prime bulb that has to be squeezed to start cold- recently i have had to squeeze it to get it to run well even while on the lake. its like it looses its prime either by sitting for a few minutes with engine off or even if i leave it idling for a few minutes when i take off it bogggs down and dies unless i squeeze the primer bulb. it will run well until i stop or idle again- any thoughts?

Re: priming carb all the time
 

Is it a MerCruiser? That would be a 4.3L V6.

A prime bulb on in inboard??? :confused: Talk about a Rube Goldberg fix. :shakehead:

Yeah. Either your carburetor needs a rebuild, you need a new fuel pump, or both. I'd start with the carb rebuild and see what happens.

The fact that it "loses prime" tends to indicate the fuel pump, to me, but you say it "runs well" once it gets above idle. What happens if you're at a decent no wake speed, say, between 1000 and 1500 RPM, and you punch it? Does she take right off or does she bog down real badly and more-or-less slowly pick up speed? What RPM and speed are you getting at WOT, with what prop?

Jim

Re: priming carb all the time
 

Where is this bulb located??? Are you able to squeeze it from the driver's seat? Is this an outboard engine?

Re: priming carb all the time
 

hey thanks guys- it does run well at idle or on accelration after its pumped up- to me its like it doesnt hold it prime and if you are not running down the lake all the time the fuel just s not there- after seeing the post you guys made i realy think the fuel pump is the right guess- i just bought this boat so is a pump bulb normal for this boat?- it is located in the engine compartment just after the fuel tank.?

any idea where the best place to get a fuel pump? it is a 4.3 liter mecr cruiser (gm v6)

Re: priming carb all the time
 

No Mike, Mercruiser engines don't have a primer bulb - you only find primer bulbs on outboard engines. Once you figure out what your fuel pressure issue it I recommend that you remove it.

Re: priming carb all the time
 

No. Like I said: It's a Rube Goldberg fix for a problem.

As to where to buy a new fuel pump: I'll leave that to someone else here. Personally, I'd call one of the local MerCruiser mechanics or dealers with which I've become acquainted since we bought Shazaam! :D (You will soon find out that being on a first-name basis with lots of local marine service centers and mechanics has its advantages ;).)

Jim

Re: priming carb all the time
 

thank you - i thought that it was odd that it had a pump bulb i wondered if it were added to cover a problem. i will replace the pump , remove the bulb and report back to the group.

Re: priming carb all the time
 

ok i went out there to take a closer look- and here is what i have- the fuel line comes out of the tank into the pump bulb, then to a filter designed like a oil filter, out to what looks like an in line filter and then to the carb. there is not a fuel pump on this engine. I looked for wires that might indicate an electric pump had been removed- but there is no evidence of a mechanical or electric pump- - im ging to look for a repair manual online that might tell me description and opertion of fuel sysytem.

Re: priming carb all the time
 

There has to be a fuel pump somewhere or it couldn't possibly run.

Jim

Re: priming carb all the time
 

I agree but if the bulb brought the fuel up, then the natural aspiration of a carb. engine is that it will pull the fuel in. i followed the line from the tank to the carb and there are no wires to indicate an electric pump and no manual pump is attached to the engine- its pretty weird to me. I own an automotive shop and I am an ASE Cetified tech but i dont get this- as I have never seen an engine run without a pump- but then again maybe thats my problem. I could easily install an electric pump and toggle it at the instrument panel. but i did not want to just add something without understanding it.